DESCRIPTION (Applicant's abstract): The long-term goal of this research program is to provide new insights into the etiology, phenomenology, course, and treatment of major depressive disorder (MDD) by integrating basic psychological research on emotion with research in psychopathology. The proposed study will specifically examine the emotional experiences of 60 outpatients with DSM-IV MDD and age- and gender-matched normal controls. It will go beyond previous studies by using a theoretically grounded taxonomy of emotions and the Experience Sampling Method (ESM) to tease apart retrospective self-report bias from self-reported experience of emotion "in the moment." Aspects of Izard's Differential Emotions Theory will be examined. This theory posits that MDD patients experience not only feelings of sadness and guilt, two emotions currently acknowledged in the diagnostic criteria, but a pattern of other powerful emotions, including fear, anger, disgust, and contempt. It further predicts that the multiple emotions observed in MDD patients become associated with each other as a result of both biological and learned processes. Based on this theory, we offer predictions about the extent to which the intensities of emotions rise and fall in synchrony over time. Participants will use the ESM to report the intensity of particular emotions 56 times over a one-week period. The within-subject intercorrelations of particular emotions over the one week period will be examined. We hypothesize that (a) MDD patients will report greater frequencies and intensities of inner directed hostility, anger, disgust, contempt, and fear, and (b) MDD patients and women will evidence higher within-subject correlations of emotions across time than controls and men. To test the first hypothesis, analyses of covariance will be conducted to determine differences between the MDD patients and controls in their reported frequencies and intensities of hostility, anger, disgust, contempt, and fear. To test the other two hypotheses, corrected within-subject correlations will be computed for each participant and converted to Fisher Z scores, which in turn will be used as dependent variables in analyses of covariance in which gender and subject will be the main predictors. Knowledge gleaned from this study will potentially aid in the assessment and treatment of patients with MDD by providing clinicians with an empirical foundation on which to base their assessments of the implications of specific emotions for MDD, and with new insights into their patients' emotional experiences.